This invention relates to a maleimide composition and a process for preparing the same.
Maleimide compounds are generally solid at ambient temperature, so that they are used in the form of powders, hydrated powders or flakes However, the powdered state of the maleimide compounds gives rise in actual operation to an increased number of operating steps and to worsened operability at the time of metering and charging. Also the maleimide compounds exhibit sublimating properties and hence are unsatisfactory hygienically.
Heretofore, as a method for preparing an aqueous suspension of maleimide compounds, there is known a method by Japanese Laid-open Patent Application No.30157/1979 which consists in pulverizing the maleimide compounds to fine powders with the mean particle size of not more than 0.5 .mu.m and mixing and dispersing the powders in a surfactant and water. However, with this method, a special equipment is required to pulverize the maleimide compounds to a particle size of not more than 0.5 .mu.m, while the problem of working environment and pollution is presented on account of the necessity of disposing of dusts and dirts. There are also many other defects that remain to be solved, viz. that the aqueous suspension of the maleimide compounds is insufficient in storage stability, and that quaternary ammonium salts and amines not only decompose peroxides as a radical polymerization initiator rapidly by ionic decomposition, but also tend to lower thermal resistance and electrical properties of polymers appreciably.